Fuel injection pump governor assembly for an internal combustion engine

ABSTRACT

A novel floating lever assembly connects a centrifugal governor and a manual speed control member to a fuel injection pump control rod, which includes yieldable means to absorb motion when the control rod is manually moved by a stopper member to stop the engine, thus preventing breakage of the governor assembly. A low speed compensation spring is engagable with the floating lever assembly to prevent excessive fuel injection volume under full load, low speed engine operation which does not affect the operation of the yieldable means.

United States Patent Isobe et al. Dec. 2, 1975 1 FUEL INJECTION PUMP GOVERNOR 2,619,080 11/1952 Weber 123/140 R ASSEMBLY FOR AN INTERNAL g; COMBUSTION ENGINE 3:672:343 6/1972 Biechl 123/140 R [75] Inventors: Hirosi Isobe; lwao Maruyama, both of Hlgashlmatsuyama Japan Primary ExaminerCharles J. Myhre [73] Assignee: Diesel Kiki Co., Ltd., Tokyo, Japan Assistant dmi l rDanil J- OCOnnOr Filed Feb 14 1974 Attorney, Agent, or FirmFrank J. Jordan [21] Appl. No.: 442,468

[57] ABSTRACT [30] F i Application priority Data A novel floating lever assembly connects a centrifugal A .20, 1973 J' 48-44146 governor and a manual Speed control member to a pr dpan fuel injection pump control rod, which includes yield- [52] US. CL 123/140 123/139 123/140 able means to absorb motion when the control rod is 123/179 manually moved by a stopper member to stop the en- [51] Int F021) U04 gine, thus preventing breakage of the governor assem- [58] Field of Search 123/140 R, 140 J 179 L, Y- A Speed COmPeISaiO spring is engagab'e l23h39 ST with the floating lever assembly to prevent excessive fuel injection volume under full load, low speed en- [56] References Cited gine operation which does not affect the operation of ld bl UNITED STATES PATENTS the we a 6 means 2,539,738 l/1951 Grim 123/140 R 6 Claims, 6 Drawing Figures 9 36 4 r 71 L WEI U.S. Patent Dec. 2, 1975 Sheet 1 of2 3,923,025

INCREASE N3 N4 N2 ENGINE SPEED Sheet 2 of 2 3,923,025

U.S. Patent Dec. 2, 1975 FUEL INJECTION PUMP GOVERNOR ASSEMBLY FOR AN INTERNAL COMBUSTION ENGINE The present invention relates to a mechanical governor assembly for a fuel injection pump for an internal combustion engine, and also to a novel lever assembly constituting a subcombination of the governor assembly which is applicable to known governor assemblies.

Existing governor assemblies, especially for Diesel engines, are arranged to sharply increase the fuel injection volume when the engine speed decreases to about 1,000 to 1,200 rpm in accordance with the no-load operating requirements of the engine. This produces satisfactory performance under light or intermediate engine loads, but under full load operation, the fuel injection volume is already just below the critical level which produces smoky exhaust gases, and the above mentioned sharp increase produces a fuel injection volume well over the critical level. The result is production of smoky exhaust gases which pollute the environment, and also a significant waste of valuable fuel.

In order to eliminate this problem, low speed compensation springs have been provided to limit the fuel injection volume to a level below critical under low speed engine operation, and to yield to allow a maximum fuel injection volume for starting the engine when the engine speed -is close to zero.

Although this arrangement prevents discharge of smoky exhaust gases at low engine speeds, it is also desirable to provide a mechanical stopper lever directly engageable with the fuel injection pump control rod to allow positive manual shut-down of the engine. Since actuation of the stopper lever would normally result in breakage of the governor assembly, a cancelling mechanism or yieldable means is provided to absorb motion of the control rod. A major problem has remained, however, in combination of a low speed compensation spring and a yieldable means, because they have been mechanically connected in series. When the low speed compensation spring is engaged with the governor assembly, it causes the yieldable means to yield, with the result that the effect of the low speed compensation spring is lost, and smoky exhaust gases are discharged from the engine under full load, low speed operation.

It is therefore an important object of the present invention to provide a governor assembly for a fuel injection pump for an internal combustion engine which provides an efficient fuel injection volume over the entire operating speed range of the engine as well as a maximum fuel injection volume for starting the engine.

It is another important object of the present invention to provide a governor assembly for a fuel injection pump for an internal combustion engine which prevents discharge of smoky exhaust gases from the engine under all productive operating conditions thereof to reduce the pollutive effect of the engine on the environment, and also to prevent waste of fuel.

It is still another important object of the invention to provide a novel lever assembly constituting a subcombination of the governor assembly of the invention including yieldable means to absorb movement of a fuel injection pump control rod when manually actuated to stop the engine which prevents breakage of the governor assembly; the lever assembly being applicable to existing governor assemblies.

The above and other objects, features and advantages of the invention will become apparant from the 2 following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals designate identical or similar elements, directions such as leftward, clockwise and upper refer to those as shown in the respective drawings, and in which:

FIG. 1 is a graph of the fuel injection characteristics of a Diesel engine presented for explanatory purposes;

FIG. 2 is a schematic view of a governor assembly to which the invention is applicable;

FIGS. 3a and 3b are schematic views of a known cancelling mechanism associable with the governor assembly of FIG. 2;

FIG. 4 is a fragmentary perspective view of a preferred embodiment of a governor assembly according to the invention; and

FIG. 5 illustrates an alternative form of the arrangement of FIG. 4, which may be used either in a governor assembly of the invention or in a known governor assembly.

Referring now to FIG. 1, the ordinate represents the fuel injection volume of a typical Diesel engine (it may also be considered as representing the axial position of the fuel injection pump control rod, since the fuel injection volume is proportional thereto), and the abscissa represents the engine speed. A line A-A' represents the critical fuel injection volume above which smoky exhaust gases are produced. A dot-dash curve B represents the fuel injection characteristics under noload engine operation. Many conventional governor assemblies are arranged to provide a solid curve C under full load engine operation, which has the same shape as the curve B in that the fuel injection volume sharply increases at a second predetermined engine speed value N Engine speeds above a value N represent a high speed range, and speeds below a value N represent a low speed range.

As is obvious from the drawing, smoky exhaust gases will never be produced under no-load engine operation, because the fuel injection volume never exceeds the critical value A-A. However, under full load operation, the fuel injection volume is normally just under the critical value A-A', and an increase therefrom as shown by the curve C will produce smoky exhaust gases at engine speeds below N The low speed compensation spring mentioned above is employed to prevent the fuel injection volume from increasing until the engine speed has dropped below a first predetermined value N.,, at which more fuel is required to prevent the engine from stalling. This arrangement is illustrated by a dashed curve D, and also provides a maximum fuel injection volume for starting the engine.

FIG. 2 shows an existing governor assembly which is improved upon by the invention. Although the modifications shown in FIG. 4 transform the governor assembly of FIG. 2 into an embodiment of the invention, it represents only one example within the scope of the invention.

A fuel control rod l0'is movable from a maximum rightward position corresponding to substantially zero fuel injection volume for stopping the engine leftward in the direction of an arrow E to increase the fuel injection volume. The fuel control rod 10 may have a rack (no numeral) fixed thereto engaging with control quadrants of control sleeves of plungers (not shown) communicating with the fuel injection pump (not shown), or be connected to control the fuel injection pump in any other manner. The control rod is pivotably connected to one end of a floating lever 12, the other end of which is connected to a speed control member 14 to be rotatable thereby. A guide lever 16 is pivotable at one end about a fixed point 25 and pivotably connected at an intermediate point 17 thereof to an intermediate point on the floating lever 12. The other end of the guide lever 16 is pivotably connected to an intermediate point of a shifter rod 18.

A centrifugal governor 20 is provided which is driven from the engine by a camshaft 22, and has flyweights 24. As the engine speed increases, the centrifugal governor 20 urges the shifter rod 18 in a first direction (rightward) to move the control rod 10 through the guide lever 16 and floating lever 12 rightward to decrease the fuel injection volume as a predetermined function of engine speed. A tension lever 23 is pivotable about the same point 25 as the guide lever 16 and is biased against a stop 26 by a compression spring 28. Second biasing means in the form of a compression idling spring 30 urge the shifter rod 18 in a second direction (leftward) against the centrifugal force developed by the flyweights 24. Biasing means in the form of a compression low speed compensation spring 32 are engagable with the control rod 10 at the point N (see FIG. 1), and a manually actuable stopper member 34 is engagable with a collar 36 fixed to the control rod 10 to move the control rod 10 to the maximum rightward position of zero fuel injection volume to stop the engine.

The centrifugal governor 20 and the speed control member 14 are in a parallel mechanical arrangement in which the control rod 10 can be moved by one of the members independently of the other, and the final position of the control rod 10 is determined by the combination of the positions of the shifter rod 18 and the speed control member 14. For example, if the shifter rod 18 is moved rightward as the engine speed increases, the guide lever 16 will be rotated counterclockwise about its fixed pivot point 25. This will move the common intermediate pivot point 17 of the guide lever 16 and the floating lever 12 approximately rightward, and the floating lever 12 will thus be displaced rightward to move the control rod 10 rightward to decrease the fuel injection volume. A conventional pin and slot assembly (no numeral) is provided between the floating lever 12 and speed control member 14 so that if, for example, the speed control member 14 is rotated clockwise, the floating lever 12 will be rotated counterclockwise about the pivot point 17 to move the control rod 10 leftward to increase the fuel injection volume.

The low speed compensation spring 32, the idling spring 30 and the centrifugal governor 20 are arranged to provide the fuel injection characteristics under full load engine operation illustrated by the dashed line curve D of FIG. 1.

The stiffness of the spring 30 is selected so that it will be forced to yield by the centrifugal force of the flyweights 24 at engine speeds above N to produce the horizontal portion of the curve C. As the engine speed drops below N the spring 30 will overcome the centrifugal force developed by the flyweights 24, and urge the shifter rod 18 leftward. At this point, the left end of the control rod 10 is arranged to engage with the spring 32, and further leftward movement of the control rod 10 is thereby prevented. The stiffness of the spring 32 is selected so that the force of the spring 30 urging the control rod 10 leftward is less than the sum of the force of the spring 32 and the centrifugal force of the flyweights 24 urging the control rod 10 rightward between the engine speeds N and N At the engine speed N the force of the spring 30 becomes equal to the opposing forces, and as the engine speed drops below N the spring 32 yields and the control rod 10 is moved leftward to produce the curve D.

In the arrangement shown in FIG. 2, if the stopper member 34 was rotated counterclockwise to move the control rod 10 rightward to stop the engine, the floating lever 12, guide lever 16, etc. would be broken. For this reason, it is desirable to incorporate a cancelling mechanism or yieldable means to absorb the movement of the control rod 10 to prevent breakage of the governor assembly.

A known cancelling mechanism is shown in FIGS. 3a and 3b, and comprises a semi-cylindrical pin 38 which is manually rotatable to control the engine speed. The speed control member 14 is bored and has a compression spring 40 disposed in the bore urging a slider block 42 against the pin 38. The pin 38 extends through a hole in the speed control member 14 perpendicularly intersecting the longitudinal axis of the bore thereof, and the speed control member 14 is thus rotatable about the pin 38. The action of the spring 40 and slider block 42 is such that the speed control member 14 is urged to the position shown in FIG. 3a, in which the flat faces of the slider block 42 and pin 38 are in contact, and the speed control member 14 is rotatable with the pin 38.

Under normal operating conditions, the speed control member 14 is rotatable with the pin 38 to control the engine speed. If, however, the control rod 10 is moved rightward by the stopper member 34 to stop the engine, the floating lever 12 will be rotated clockwise about the point 17. This will result in counterclockwise rotation of the speed control member 14 about the pin 38 against the force of the spring 40 to the position shown in FIG. 3b. In this way, the motion of the control rod 10 is absorbed to prevent breakage of the governor assembly. As soon as the stopper member 34 is released, the speed control member 14 will be returned to the position of FIG. 3a and be again rotatable with the pin 38.

The arrangement shown by FIGS. 2 and 3a and 3b in combination suffers a serious drawback, however, in that if the engine speed is below N the low speed compensation spring 32 and the spring 40 of the cancelling mechanism or yieldable means are mechanically connected in series, and interfere with each others operation. If, for example, the stiffness of the spring 32 was greater than the stiffness of the spring 40, the spring 40 would yield at N to produce the curve C rather than the curve D. Thus, smoky exhaust gases would be produced with subsequent waste of fuel, and the advantage of the low speed compensation spring 32 would be lost.

This problem is overcome by the arrangement of FIG. 4 which illustrates the basic principles of the invention, and the arrangement of FIG. 3 taken in conjunction with the modifications thereto shown in FIG. 4 constitutes a preferred embodiment of a governor assembly of the invention.

In FIG. 4, the speed control member 14 is solidly fixed to the pin 38, which is manually rotatable through a linkage (not designated). The floating lever 12 of FIG. 3 is replaced by a novel floating lever assembly comprising a first lever 44 and a second lever 46. A shaft 48 is fixed to the first lever 44, and the guide lever 16 is rotatable about the shaft 48. One end of the first lever 44 is rotatable by the speed control member 14, and the other end is engagable with a low speed compensation spring 33, which is here shown as being a tension spring having a hook 33a. The second lever 46 has a sleeve 50 fixed thereto having a circumferential cutout as shown. The sleeve 50 and thus the second lever 46 are rotatable about the shaft 48, and an end of the second lever 46 is pivotably connected to the control rod 10. A pin 52 fixed to the shaft 48 extends through the cutout of the sleeve 50. Yieldable means in the form of a coil spring 54 engage with the pin 52 and the second lever 46 to rotatably urge the second lever 46 in a direction to move the control rod in the direction to increase the fuel injection volume.- The pin 48 is normally held in engagement with a circumferential edge of the cutout by the force of the spring 54 so that the first and second lever 44 and 46 respectively are movable as a unit.

At engine speeds above N the arrangement of FIG. 4 operates identically with the arrangement of FIG. 2. At N however, the first lever 44 engages with the hook 33a of the spring 33, and further movement of the first lever 44 and thus the second lever 46 and the control rod 10 in the direction to increase the fuel injection volume is opposed by the force of the spring 33 to produce the curve D. If the stopper member 34 is actuated to stop the engine, the second lever 46 will be rotated about the shaft 48 againstthe force of the spring 54, and the motion of the control rod 10 will be absorbed to prevent breakage of the governor assembly. It will be noted that the springs 33 and 54 are mechanically connected in parallel and act independently of each other, so that adverse interaction therebetween is prevented. The circumferential width of the cutout is selected so that the movement of the control rod 10 will be completely absorbed by rotation of the second lever 46 about the shaft 48 when the stopper member 34 is actuated to stop the engine. The spring 54 is stiff enough so that it will yield only when the stopper member 34 is actuated.

An alternative form of the floating lever assembly is shown in FIG. 5, which may also be used as an element in other types of governor assemblies. The first lever 44 is the same as that of FIG. 4, and is not shown. In this case, however, a second lever 46' is rigidly fixed to a shaft 48'. A second shaft 56 is provided which is fixed to the second lever 46. The sleeve 50 is fixed to a third lever 58, and is rotatable therewith about the second shaft 56. The pin 52 is fixed to the second shaft 56, and the spring 54 engages with the pin 52 and the third lever 58. An end of the third lever 58 is pivotably connected to the control rod 10. Operation is identical with the floating lever assembly of FIG. 4 except that the third lever 58 rotates about the second shaft 56 when the stopper member 34 is actuated to stop the engine.

It will be understood that the scope of the invention also includes a governor assembly having a centrifugal governor but no speed control member which may be used with a single speed engine, in which case the governor assembly would respond only to changes in engine loading. The floating lever assembly of FIG. 5 is especially suited to this type of application.

What is claimed is:

l. A fuel injection pump governor assembly, comprising:

6 a fuel injection pump control rod movable from a position to provide substantially zero fuel injection volume in a direction to increase the fuel injection volume;

an engine driven centrifugal governor operatively connected to said control rod to urge said control rod toward said position of substantiallyzero fuel injection volume as a predetermined function of engine speed;

a stopper member manually actuable to move said 1 control rod to said position of substantially zero fuel injection volume;

yieldable means disposed between said centrifugal governor and said control rod and arranged to yield only when said control rod is moved by said stopper member to said position of substantially zero fuel injection volume to prevent breakage of said governor assembly; and

biasing means engagable with said yieldable means when said control rod has moved to a predetermined position in said direction to increase the fuel injection volume; the stiffness of said biasing means being selected so that further movement of said control in said direction is possible only if the engine speed is below a first predetermined value; and

said yieldable means and said biasing means being arranged so that said yieldable means yields only when said stopper member is actuated to move said control rod to said position of substantially-zero fuel injection volume even if said biasing means is in engagement therewith. 1

2. A governor assembly according to claim 1, further comprising a speed control member connected in a parallel mechanical arrangement with said centrifugal governor and being manually movable to move said control rod in conjunction with said centrifugal governor.

3. -A governor assembly according to claim 2, in which said centrifugal governor includes a shifter rod which is moved in a first direction to urge said control rod toward said position of substantially zero fuel injection volume as a predetermined function of engine speed;

second biasing means arranged to urge said shifter rod in a second direction opposite to said first direction, the stiffness of said second biasing means being selected so that said second biasing means yields only if the engine speed is above a second predetermined value higher than said first predetermined value;

a guide lever having one end pivotably connected to a fixed point of the governor assembly and the other end pivotably connected to said shifter rod; a floating lever assembly rotatable at an intermediate point thereof about an intermediate point of said guide lever and having one end pivotably connected to said control rod and the other end connected to said speed control member for rotation thereby; and in which I said yieldable means is an integral part of said floating lever assembly and said biasing means is engagable with said floating lever assembly.

4. A governor assembly according to claim 3, in which said floating lever assembly comprises:

a first lever having a shaft rotatable therewith about said intermediate point of said floating lever assem- 7 bly, said intermediate point of said guidelever being rotatably connected to said shaft;

one end of said first lever being connected to said speed control member for rotation thereby, and said first lever being engagable with said biasing means;

a second lever having an end pivotally connected to said control rod and a sleeve fixed thereto rotatable about said shaft, said sleeve being formed with a circumferential cutout;

a pin fixed to said shaft and extending through said cutout; and

a spring constituting said yieldable means engaging 5. A governor assembly according to claim 3, in which said floating lever assembly comprises:

a first lever having a shaft rotatable therewith about said'intermediate point of said floating lever assembly, said intermediate point of said guide lever being rotatably connected to said shaft, one end of said first lever being connected to said speed control member for rotation thereby, and said first lever being engagable with said biasing means;

a second lever rotatably with said shaft; a third lever having one end pivotally connected to said control rod;

a second shaft fixed to one of said second and third levers;

a sleeve fixed to the other of said second and third levers and being rotatable about said second shaft, said sleeve being formed with a circumferential cutout;

a pin fixed to said second shaft and extending through said cutout; and

a spring constituting said yieldable means and engaging with said pin and the one of said second and third levers to which said sleeve is fixed to rotatably bias said third lever in a direction to urge said control rod in said direction to increase the fuel injection volume, a circumferential edge of said cutout normally being held in engagement with said pin by said spring, and the circumferential width of said cutout being selected so that said third lever may be rotated against the force of said spring about said second shaft when said stopper member is actuated to move said control rod to said position of substantially zero fuel injection volume.

6. In a fuel injection pump governor assembly including a fuel injection control rod movable from a position to provide substantially zero fuel injection volume in a direction to increase the fuel injection volume, a centrifugal governor, and a stopper member manually actuable to move the control rod to the position of substantially zero fuel injection volume, a floating lever assembly to connect the centrifugal governor to the control rod, comprising:

a first lever arranged for connection with the centrifugal governor;

a second lever arranged for connection with the control rod;

a shaft fixed to one of said first and second levers;

a sleeve fixed to the other of said first and second levers and being rotatable about said shaft, said sleeve being formed with a circumferential cutout; pin fixed to said shaft and extending through said cutout; and spring engaging with said pin and the one of said first and second levers to which said sleeve is fixed to rotatably bias said second lever in a direction to move the control in the direction to increase the fuel injection volume, a circumferential edge of said cutout normally being held in engagement with said pin by said spring, and the circumferential width of said cutout being selected so that said second lever may be rotated against the force of said spring about said shaft when the stopper member is actuated to move said control rod to said position of substantially zero fuel injection volume to prevent breakage of the governor assembly. 

1. A fuel injection pump governor assembly, comprising: a fuel injection pump control rod movable from a position to provide substantially zero fuel injection volume in a direction to increase the fuel injection volume; an engine driven centrifugal governor operatively connected to said control rod to urge said control rod toward said position of substantially zero fuel injection volume as a predetermined function of engine speed; a stopper member manually actuable to move said control rod to said position of substantially zero fuel injection volume; yieldable means disposed between said centrifugal governor and said control rod and arranged to yield only when said control rod is moved by said stopper member to said position of substantially zero fuel injection volume to prevent breakage of said governor assembly; and biasing means engagable with said yieldable means when said control rod has moved to a predetermined position in said direction to increase the fuel injection volume; the stiffness of said biasing means being selected so that further movement of said control in said direction is possible only if the engine speed is below a first predetermined value; and said yieldable means and said biasing means being arranged so that said yieldable means yieldS only when said stopper member is actuated to move said control rod to said position of substantially zero fuel injection volume even if said biasing means is in engagement therewith.
 2. A governor assembly according to claim 1, further comprising a speed control member connected in a parallel mechanical arrangement with said centrifugal governor and being manually movable to move said control rod in conjunction with said centrifugal governor.
 3. A governor assembly according to claim 2, in which said centrifugal governor includes a shifter rod which is moved in a first direction to urge said control rod toward said position of substantially zero fuel injection volume as a predetermined function of engine speed; second biasing means arranged to urge said shifter rod in a second direction opposite to said first direction, the stiffness of said second biasing means being selected so that said second biasing means yields only if the engine speed is above a second predetermined value higher than said first predetermined value; a guide lever having one end pivotably connected to a fixed point of the governor assembly and the other end pivotably connected to said shifter rod; a floating lever assembly rotatable at an intermediate point thereof about an intermediate point of said guide lever and having one end pivotably connected to said control rod and the other end connected to said speed control member for rotation thereby; and in which said yieldable means is an integral part of said floating lever assembly and said biasing means is engagable with said floating lever assembly.
 4. A governor assembly according to claim 3, in which said floating lever assembly comprises: a first lever having a shaft rotatable therewith about said intermediate point of said floating lever assembly, said intermediate point of said guide lever being rotatably connected to said shaft; one end of said first lever being connected to said speed control member for rotation thereby, and said first lever being engagable with said biasing means; a second lever having an end pivotally connected to said control rod and a sleeve fixed thereto rotatable about said shaft, said sleeve being formed with a circumferential cutout; a pin fixed to said shaft and extending through said cutout; and a spring constituting said yieldable means engaging with said pin and said second lever to rotatably bias said second lever in a direction to urge said control rod in said direction to increase the fuel injection volume, a circumferential edge of said cutout normally being held in engagement with said pin by said spring, and the circumferential width of said cutout being selected so that said second lever may be rotated against the force of said spring about said shaft when said stopper member is actuated to move said control rod to said position of substantially zero fuel injection volume.
 5. A governor assembly according to claim 3, in which said floating lever assembly comprises: a first lever having a shaft rotatable therewith about said intermediate point of said floating lever assembly, said intermediate point of said guide lever being rotatably connected to said shaft, one end of said first lever being connected to said speed control member for rotation thereby, and said first lever being engagable with said biasing means; a second lever rotatably with said shaft; a third lever having one end pivotally connected to said control rod; a second shaft fixed to one of said second and third levers; a sleeve fixed to the other of said second and third levers and being rotatable about said second shaft, said sleeve being formed with a circumferential cutout; a pin fixed to said second shaft and extending through said cutout; and a spring constituting said yieldable means and engaging with said pin and the one of said second and third levers to which said sleeve is fixed to rotatably bias said third lever in a direction to urge sAid control rod in said direction to increase the fuel injection volume, a circumferential edge of said cutout normally being held in engagement with said pin by said spring, and the circumferential width of said cutout being selected so that said third lever may be rotated against the force of said spring about said second shaft when said stopper member is actuated to move said control rod to said position of substantially zero fuel injection volume.
 6. In a fuel injection pump governor assembly including a fuel injection control rod movable from a position to provide substantially zero fuel injection volume in a direction to increase the fuel injection volume, a centrifugal governor, and a stopper member manually actuable to move the control rod to the position of substantially zero fuel injection volume, a floating lever assembly to connect the centrifugal governor to the control rod, comprising: a first lever arranged for connection with the centrifugal governor; a second lever arranged for connection with the control rod; a shaft fixed to one of said first and second levers; a sleeve fixed to the other of said first and second levers and being rotatable about said shaft, said sleeve being formed with a circumferential cutout; a pin fixed to said shaft and extending through said cutout; and a spring engaging with said pin and the one of said first and second levers to which said sleeve is fixed to rotatably bias said second lever in a direction to move the control in the direction to increase the fuel injection volume, a circumferential edge of said cutout normally being held in engagement with said pin by said spring, and the circumferential width of said cutout being selected so that said second lever may be rotated against the force of said spring about said shaft when the stopper member is actuated to move said control rod to said position of substantially zero fuel injection volume to prevent breakage of the governor assembly. 